I'm liking my female undead rogue, the flips makes things more exciting! I also am liking my female orc monk, I was shocked to find out the model goes very well with the class, and my transmog makes it look all the better!

Worgen Male Warrior/Rogue - Seems to work fairly well for a Worgen. Especially a Warrior using Titan's Grip and wearing the Wrathful PVP Set
Human Male in Warrior T10 - Armor just fits perfectly, one of the reasons I made a Human Paladin
Tauren Male Warrior - Pretty much says 'I'm the tank'.
Undead Male Rogues - Deathstalkers help make this one of my favourite class/race combos